BIG PHYSICS, BIG QUESTIONS –

Enzyme could provide ‘chemical liposuction’

A collagen-dissolving drug that is showing early promise in treating fatty tumours in people might one day be used to fight obesity, says a US company. It has already slimmed down obese mice.

Biospecifics, based in New York, has developed a concentrated, purified form of collagenase – a natural enzyme that breaks down collagen in cells. “Like all cells, fat cells are held together by collagen – once the collagen is hydrolysed, the cells liquefy,” says Tom Wegman, executive vice president. Injections of the enzyme are carefully localised to prevent other cells being damaged.

The drug is currently being given to 12 patients with small lipomas. These fat-filled, non-malignant growths are usually surgically removed. But injections of the drug have shrunk the tumours significantly in 10 of the patients so far.

In seven patients, the shrinkage has been greater than 50 per cent. But it is not yet clear what happens to the fat once the cells are broken down.

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“There’s no reason why fat in other parts of the body wouldn’t respond in the same way,” Wegman told New Scientist. “But we’d need to do well-controlled studies to show this, and we have not done that yet.”

Charred tissue

Biospecifics’ collagenase is already used to remove charred, dead tissue when treating severe burns. And early trials of the drug on animals have demonstrated its fat-busting potential, says Wegman.

The researchers then injected the collagenase into fat pads of rats bred to be obese. These pads disappeared, the company reports. “We did think then that this might become a kind of chemical liposuction,” he says.

Even if the drug only proves useful for treating lipomas, that will be a significant achievement, Wegman says. “We have yet to decide whether we want to investigate its effects for removing body fat. To become licensed as a chemical liposuction in the US would be an expensive proposition.”

However, an alternative to physical liposuction could be very lucrative, Wegman admits. In 2001, doctors conducted about 800,000 liposuction procedures in the US alone.